The invention relates generally to medical devices and more particularly to side-firing optical fibers and methods for using such devices.
Laser-based surgical procedures using side-firing optical fibers can provide a medical practitioner with more control when applying laser energy to the appropriate treatment area. Passing the distal end portion of the optical fiber through an endoscope during surgery, however, may damage, scratch, degrade, and/or deform the distal end portion of the optical fiber. To protect the optical-fiber end portion, a capillary and/or a metal cap or cannula, usually made of surgical grade stainless steel, can be placed over the optical-fiber end portion. Once the distal end portion of the optical fiber is properly positioned for treatment, the laser energy can be applied to the target area.
During use of the device, a portion of the laser energy can leak from the distal end portion of the optical fiber, reducing the efficiency with which laser energy is delivered to the treatment area and/or increasing overheating of the metal cap that is typically used to protect the optical fiber. Cooling of the device may be needed to operate at a safe temperature. In some instances, the overheating that can occur from the laser energy leakage can affect the mechanical and/or optical properties of the optical-fiber end portion, the capillary and/or the metal cap. In other instances, the overheating that can occur from the laser energy leakage can be sufficiently severe to damage the optical-fiber end portion, the capillary and/or the metal cap.
Overheating can also occur from the use of reflectors such as metallic reflectors or tips configured to redirect or bend an optical beam about 90 degrees from its original propagation path based on total internal reflection (TIR). Because metallic reflectors do not reflect 100% of the optical beam, the energy associated with the non-reflected portion of the optical beam can be absorbed by the metallic reflector and the metallic reflector can self heat. For TIR-based tips, a portion of the optical beam can leak through and heat up a protective metal cap positioned on a distal end of the tip. Furthermore, the glass capillary tubing that is generally used on the TIR-based tips can become damaged as tissue is ablated and impact against the glass capillary tubing.
Thus, a need exists for optical-fiber end portions that can increase side-fired laser energy, increase device longevity, increase transmission efficiency, reduce overheating, and/or increase patient safety.